The overall objectives of this project are to investigate the pathologic and pathophysiologic processes of optic disc edema associated with experimental systemic hypertension or occlusion of posterior ciliary arteries in monkeys; to examine the pathologic and pathophysiologic processes of optic nerve head associated with chronic or subacute elevation of intraocular pressure in monkey and man; and to examine the interstitial fluid exchange around the optic disc head in various experimental models of dogs or monkey with optic pit with or without retinal detachment.